Execute is a very powerful attack, but one that requires a bit of timing and practice. The base 30 Rage is unlikely to finish the remaining 20% of the target's health in one hit.

The emptying of the Rage Bar means that you will be left with no rage for the next fight. The introduction of [Victory Rush] has reduced this disadvantage, but it is recommended that you recast [Battle Shout] before using execute to finish off your opponent. This will allow you to attack your next target without having to waste rage to re-buff yourself.

Patch 5.1.0 (27-Nov-2012): Execute damage with high amounts of Vengeance is now capped at the Warrior's maximum health to prevent it from reaching excessive numbers.

Patch 3.2.0 (04-Aug-2009): This ability now never costs more than a total of 30 rage. The tooltip for Sudden Death has been revised to remove reference to that maximum, since the ability now behaves that way even when untalented.; Focused Rage and the Dreadnaught Battlegear set bonus will now properly reduce the cost of Execute.

Patch 2.1.0 (22-May-2007): When used with Sweeping Strikes, ranks 6 and 7 of this ability will no longer cause full damage to secondary targets who are not wounded.

Patch 1.3.0 (07-Mar-2005): Full rage is no longer consumed when the ability does not hit.